Bismuth trioxide

Bismuth(III) oxide

Names
IUPAC names Bismuth trioxide Bismuth(III) oxide Bismite (mineral)
Other names Bismite, bismuth sesquioxide
Identifiers
CAS Number	1304-76-3 Y
3D model (Jmol)	Interactive image
ChemSpider	14093 Y
ECHA InfoCard	100.013.759
UNII	A6I4E79QF1 Y
InChI InChI=1S/2Bi.3O Y Key: WMWLMWRWZQELOS-UHFFFAOYSA-N Y InChI=1/2Bi.3O/rBi2O3/c3-1-5-2-4 Key: WMWLMWRWZQELOS-JOBWJGIYAA
SMILES O=[Bi]O[Bi]=O
Properties
Chemical formula	Bi2O3
Molar mass	465.96 g/mol
Appearance	yellow crystals or powder
Odor	odorless
Density	8.90 g/cm3, solid
Melting point	817 °C (1,503 °F; 1,090 K)
Boiling point	1,890 °C (3,430 °F; 2,160 K)
Solubility in water	insoluble
Solubility	soluble in acids
Magnetic susceptibility (χ)	-83.0·10−6 cm3/mol
Structure
Crystal structure	monoclinic, mP20, Space group P21/c (No 14)
Coordination geometry	pseudo-octahedral
Hazards
Safety data sheet	See: data page MallBaker MSDS
EU classification (DSD)	not listed
NFPA 704	0 1 0
Flash point	Non-flammable
Related compounds
Other anions	Bismuth trisulfide
Other cations	Arsenic trioxide Antimony trioxide
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Bismuth(III) oxide is perhaps the most industrially important compound of bismuth. It is also a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite (tetragonal, much more rare), but it is usually obtained as a by-product of the smelting of copper and lead ores. Bismuth trioxide is commonly used to produce the "Dragon's eggs" effect in fireworks, as a replacement of red lead.

The structures adopted by Bi₂O₃ differ substantially from those of arsenic(III) oxide, As₂O₃, and antimony(III) oxide, Sb₂O₃.

Bismuth oxide, Bi₂O₃ has five crystallographic polymorphs. The room temperature phase, α-Bi₂O₃ has a monoclinic crystal structure. There are three high temperature phases, a tetragonal β-phase, a body-centred cubic γ-phase, a cubic δ-Bi₂O₃ phase and an ε- phase. The room temperature α-phase has a complex structure with layers of oxygen atoms with layers of bismuth atoms between them. The bismuth atoms are in two different environments which can be described as distorted 6 and 5 coordinate respectively.

β-Bi₂O₃ has a structure related to fluorite.

γ-Bi₂O₃ has a structure related to that of Bi₁₂SiO₂₀ (a sillenite), where a fraction of the Bi atoms occupy the position occupied by Si^IV, and may be written as Bi₁₂Bi_0.8O_19.2.